Electrical connector



Oct. 10, 1967 J. BuRNzsToN ELECTRICAL CONNECTOR Filed July 19, 1965 INVENTOR.

RAYMOND J. BURNiSTON ATTORNEY United States Patent 3,346,835 ELECTRICAL CONNECTOR Raymond J. Buruiston, Old Bridge, N.J., assignor to Buchanan Electrical Products Corporation, Union, N.J., a corporation of New Jersey Filed July 19, 1965, Ser. No. 472,818 7 Claims. (Cl. 339-272) ABSTRACT OF THE DISCLOSURE In an electrical connector of the type having a tubular body and a clamping screw threaded through a tapped hole in the wall of the body for clamping an electrical conductor within the body, a unitary clamping jaw assembled with the bottom of the clamping screw by means of a swivel connection and having a pressure plate portion with a diameter no greater than the inside diameter of the tapped hole and at least one integral resiliently defiectable tab normally inclined upwardly from the pressure plate portion toward the top of the clamping screw and radially outwardly such that the clamping jaw may be inserted downwardly through the tapped hole by resilient deflection of the tab laterally inwardly to present an overall diameter smaller than the inside diameter of the tapped hole and after passing through the tapped hole, the tab will return laterally outwardly below the bottom of the portion of the wall through which the clamping screw is passed to preclude removal of the clamping screw by engagement of the tab with the bottom of that wall portion and to preclude rotation of the clamping jaw relative to the electrical conductor by engagement of the tab with a side portion of the wall of the body.

This invention relates to electrical connectors, and more particularly to such connectors as are used in terminal blocks, panel boards, and the like.

Such connectors have a body generally comprised of a substantially rectangular tube, and a screw passing through the top portion of the wall of the tube for clamping an electrical conductor against the bottom of the tube. To prevent rotation of the clamping screw from marring the conductor, it is desirable to have a swivel jaw on the bottom of the screw. It is also desirable to provide a catch to prevent removal and consequent loss of the screw. It has been proposed to insert the swivel jaw for the clamping screw endwise into the rectangular tube, then insert the clamping screw down through a tapped hole in the top of the tube, and effect a swivel joint inside the tube. However, this has involved excessive difficulties of access and manipulation. I It is therefore an important object of the present invention to provide a captive swivel jaw which can be preassembled with the clamping screw and can then be contracted and inserted down through the tapped threads in the top portion, and thereafter expanded to prevent removal of the screw.

According to the present invention, the electrical connector comprises an electrically conductive substantially rectangular tube, drilled and tapped to receive a subassembly of a clamping screw and a captive swivel jaw and catch which prevents the screw from separating from the tube once assembled to it, and provides a pressure plate for compressing electrical wire conductors against the bottom of the tube. V This captive sub-assembly is inserted into a tapped hole Patented Oct. 10, 1967 in a rectangular tube. Subsequent turning of the screw advances the screw and swivel jaw downwardly toward the bottom inside surface of the tube. The swivel jaw is held captive to the bottom of the screw, and is free to follow the screw bottom downward into the tube during this advancement, but is not free to rotate with the screw. Thus the swivel jaw acts as a non-rotating pressure plate to provide the clamping action required to compress a wire conductor or group thereof that may be caught between the swivel jaw and the inside floor of the tube. A hole or opening in the bottom pressure plate portion of the swivel jaw coaxial with the screw serves to compress impressions in the conductors to provide a more secure connection between the conductors and the tube.

As the screw is turned to withdraw it from the tapped hole in the top of the tube, the swivel jaw which is held captive to the bottom tip of the screw, is forced to follow the bottom tip of the screw away from the bottom of the tube. However, spring tabs, fingers, or hinged out extensions of the swivel jaw prevent withdrawal thereof beyond the inside of the upper wall of the tubular member. The threaded portion of the screw is at this time clear of the tapped opening in the top of the tube. Therefore, the thread engagement no longer exists between the screw and the tube, and no further screw thread is available to force the captive swivel jaw either olT of the screw tip, or out of the tube. The screw and swivel jaw assembly thereby remains captivated in the rectangular tube and available for advancement into the tube, but not out of it.

To accomplish this captivated function, the bottom tip of the screw has a flat diametral surface equal to a value smaller than the root diameter of the screw thread. A short distance above this fiat surface toward the screw head is an annular undercut groove which serves for holding the swivel jaw onto the flat diametral surface. This groove leaves a neck or stem connecting the flat surface tip to the main threaded portion of the screw.

The swivel jaw can be of cup shape, the main body of which is large enough in internal diameter to receive the full depth of the flat diametral surface tip of the screw, yet smaller in outside diameter than the root diameter of the screw thread or the inside diameter of the tapped hole. This swivel jaw is provided with fingers extending upward from the side wall of the cup-shaped piece which can be bent inward above the flat tip and into the undercut thereabove. The swivel jaw is also provided with tabs that extend to a diameter larger than the root diameter of the screw thread and the inside diameter of the tapped hole when assembled to the screw, permitting them to be forced inward to the root diameter and pass through the tapped hole as the screw tip enters the tapped hole in the tube, and once through the tapped hole in the upper wall of the tube, these tabs spring outward again to prevent passage of the swivel jaw through the tapped hole upon retraction of the screw.

In the drawings:

FIGURE 1 is an assembly end view partly in vertical cross section through an electrical connector according to a preferred embodiment of the present invention;

FIGURE 2 is a plan of the captive jaw blank before assembly thereof; and

FIGURE 3 is a vertical section through the captive jaw blank shown in FIGURE 2, and taken along the line 3-3 thereof.

The electrical connector shown in the drawings com- 3 prises a top portion 10, a bottom portion 12, and at least one side portion 14 which holds the portions 10 and 12 in spaced relation, and preferably forming .a substantially rectangular body in the form of a tube or ferrule of conductive material such as metal.

The top portion 10 has a tapped hole 16 to receive a metal clamping screw 18. The screw 18 has a unitary captive jaw 20 assembled with the screw 18 at the bottom thereof witha swivel connection, and movable thereby toward the bottom portion 12 to clamp an electrical conductor therebetween. The clamping screw 18 has an annular groove 24 near the bottom thereof, and the captive jaw 20 has at least one integral lateral projection 26 bent upward and inward into the annular groove 24 to form the swivel connection between the captive jaw 20 and the screw 18.

The jaw 20 has at least one integral tab or projection 22 extending laterally beyond the crest diameter of the tapped threads. This projection 22 is resiliently yieldable and inclined upwardly and outwardly from the swivel axis, whereby the captive jaw 20 may be inserted downwardly inside the tapped hole by camming or deflecting the projection 22 inward, so as to snap back under the threads after the projection has passed below the bottom of the top portion 10. Preferably the captive jaw 20 has at least a pair of such projections extending in opposite directions.

The distance from the top of the groove 24 to the top of the projection 22 is greater than the thickness of the top portion 10, whereby upon reversal of the rotation of the screw 18, the ascending screw 18 leaves the threads of tapped hole 16 before a projection 22 of the captive jaw 20 reaches the bottom of the top portion 10.

The captive jaw 20 is preferably formed of a one piece metal blank which is resiliently yieldable, and a hole 28 is formed in the bottom pressure plate portion thereof to make an impression in the conductor being clamped by the pressure plate portion to increase the grip thereon.

What is claimed is:

1. An electrical connector comprising:

a body including a top portion of predetermined thickness having a top and a bottom, a bottom portion and at least one side portion maintaining said top and bottom portions in spaced relation;

a tapped hole in the top portion;

a clamping screw received within the tapped hole and having a threaded portion lying between a top and a bottom; and

a unitary captive jaw assembled with the clamping screw at the bottom thereof in swivel connection therewith for permitting relative rotation between the clamping screw and the captive jaw about a vertical swivel axis and vertical movement of the captive jaw relative to the bottom portion of the body in response to the advancement of the clamping screw within the tapped hole to clamp an electrical conduc-. tor between the captive jaw and said bottom portion;

said captive jaw having a pressure plate portion'juxtaposed with the bottom of the clamping screw and having a diameter no greater than the inside diameter of the tapped hole, and at least one integral projection normally extending laterally outwardly beyond the inside diameter of said tapped hole, said projection being resiliently yieldable and inclined upwardly from the pressure plate portion toward the top of the clamping screw and outwardly from the swivel axis such that the captive jaw may be passed downwardly through the tapped hole by resilient flexing of the projection laterally inwardly to present an overall diameter no greater than the inside diameter of the tapped hole and upon passage of the captive jaw through said tapped hole, the projection will return laterally outwardly to preclude retraction of the clamping screw from the tapped hole by engagement of the projection with the bottom of the top portion of the body and to preclude rotation of the captive jaw by engagement of the projection with the side portion of the body during rotation of the clamping screw.

2. The electrical connector of claim 1 wherein said clamping screw has an annular groove near the bottom thereof, and said captive jaw has at least one integral lateral projection extending axially upwardly from the pressure plate portion and laterally inwardly into said annular groove to establish said swivel connection between the clamping screw and the captive jaw.

3. The electrical connector of claim 2 wherein the distance from the top of said annular groove to the top of the resiliently yieldable projection is greater than the thickness of the top portion of the body so that upon reversal of the rotation of the clamping screw, the threaded portion of the ascending clamping screw will leave the tapped hole before the resiliently yieldable projection of the captive jaw engages the bottom of said top portion.

4. The electrical connector of claim 1 wherein the body has a substantially rectangular tubular configuration.

5. The electrical connector of claim 1 in which the pressure plate portion of the captive jaw has a hole therein for making an impression in theconductor being clamped in the connector to increase the grip thereon.

6. The electrical connector of claim 1 wherein said captive jaw has at least two of said resiliently yieldable projections extending from the pressure plate portion in opposite directions.

7. An electrical connector comprising:

a tubular body having a generally-rectangular configuration including a top portion of predetermined thickness having a top and a bottom, a bottom portion and side portions maintaining said top and bottom portions in spaced relationship;

a tapped hole in the top portion;

a clamping screw received within the tapped hole and having a threaded portion lying between a top and a bottom and an annular groove near the bottom thereof; and

a unitary captive jaw assembled with the clamping screw at the bottom thereof in swivel connection therewith for permitting relative rotation between the clamping screw and the captive jaw about a vertical swivel axis and vertical movement of the captive jaw relative to the bottom portion of the body in response to the advancement of the clamping screw within the tapped hole to clamp an electrical conductor between the captive jaw and said bottom portion;

said captive jaw having a pressure plate portion juxtaposed with the bottom of theclamping screw and having a diameter no greater than the inside diameter of the tapped hole, a plurality of integral tabs spaced around the periphery of the pressure plate portion and normally extending laterally outwardly be yond the inside diameter of said tapped hole, said tabs being resiliently deflectable and inclined upwardly from the pressure plate portion toward the top of the clamping screw and outwardly from the swivel axis such that the captive jaw maybe passed downwardly through the tapped hole by resilient deflection of the tabs laterally inwardly to present an overall diameter no greater than the inside diameter of the tapped hole and upon passage of the captive jaw through said tapped hole, the tabs will return laterally outwardly to preclude retraction of the clamping screw from the tapped hole by engagement of the tabs with the bottom of the top portion of the body and to preclude rotation of the captive jaw by engagement of the tabs with the side portions of the body during rotation of the clamping screw, and a plurality of integral fingers spaced about the periphcry of the pressure plate portion between the spaced I tabs and extending axially upwardly from the pressure plate portion and laterally inwardly into said annular groove in the clamping screw to establish said swivel connection between the clamping screw and the captive jaw.

References Cited UNITED STATES PATENTS 1,560,296 11/1925 Mahaffey 15169 X 2,132,967 10/1938 Pennell 339272 6 2,222,156 11/ 1940 Rowe 339-272 2,285,928 6/ 1942 Jensen 33927 2 3,144,293 8/ 1964 De Smidt 339244 FOREIGN PATENTS 926,312 4/ 1955 Germany.

1,071,794 12/1959 Germany. MARVIN A. CHAMPION, Primary Examiner.

P. TEITELBAUM, Assistant Examiner. 

1. AN ELECTRICAL CONNECTOR COMPRISING: A BODY INCLUDING A TOP PORTION OF PREDETERMINED THICKNESS HAVING A TOP AND A BOTTOM, A BOTTOM PORTION AND AT LEAST ONE SIDE PORTION MAINTAINING SAID TOP AND BOTTOM PORTIONS IN SPACED RELATION; A TAPPED HOLE IN THE TOP PORTION; A CLAMPING SCREW RECEIVED WITHIN THE TAPPED HOLE AND HAVING A THREADED PORTION LYING BETWEEN A TOP AND A BOTTOM; AND A UNITARY CAPTIVE JAW ASSEMBLED WITH THE CLAMPING SCREW AT THE BOTTOM THEREOF IN SWIVEL CONNECTION THEREWITH FOR PERMITTING RELATIVE ROTATION BETWEEN THE CLAMPING SCREW AND THE CAPTIVE JAW ABOUT A VERTICAL SWIVEL AXIS AND VERTICAL MOVEMENT OF THE CAPTIVE JAW RELATIVE TO THE BOTTOM PORTION OF THE BODY IN RESPONSE TO THE ADVANCEMENT OF THE CLAMPING SCREW WITHIN THE TAPPED HOLE TO CLAMP AN ELECTRICAL CONDUCTOR BETWEEN THE CAPTIVE JAW AND SAID BOTTOM PORTION; 